These are artistic representations of the top planets around other stars (exoplanets) with any potential to support liquid surface water. All of them are larger than Earth and we are not certain about their composition and habitability yet. We only know that they seem to have the right size and orbit to support surface liquid water. They are ranked here from closest to farthest from Earth. This selection of objects of interest is subject to change as new interpretations or astronomical observations are made. Earth, Mars, Jupiter, and Neptune are shown for scale on the right.

Superterran(Super-Earth/Mini-Neptunes)

Total

1

21

30

52

Conservative Sample of Potentially Habitable Exoplanets

This is a list of the exoplanets that are more likely to have a rocky composition and maintain surface liquid water (i.e. 0.5 < Planet Radius ≤ 1.5 Earth radii or 0.1 < Planet Minimum Mass ≤ 5 Earth masses, and the planet is orbiting within the conservative habitable zone). They are represented artistically in the top image.

Optimistic Sample of Potentially Habitable Exoplanets

This is a list of the exoplanets that are less likely to have a rocky composition or maintain surface liquid water (i.e. 1.5 < Planet Radius ≤ 2.5 Earth radii or 5 < Planet Minimum Mass ≤ 10 Earth masses, or the planet is orbiting within the optimistic habitable zone).

Teq - Equilibrium temperature in kelvins (K) assuming a 0.3 bond albedo (Earth = 255 K). Actual surface temperatures are expected to be larger than the equilibrium temperature depending on the atmosphere of the planets, which are currently unknown (e.g. Earth mean global surface temperature is about 288 K or 15°C).

Period - Orbital period in days (Earth = 365 days).

Distance - Distance from Earth in light years (ly).

ESI - Earth Similarity Index, a measure of similarity to Earth that summarizes how similar are these planets to the stellar flux, mass, and radius of Earth (Earth = 1.0). Results are sorted by this number. Planets more similar to Earth are not necessarily more habitable, since the ESI does not consider all factors necessary for habitability.

The figure above shows all planets near the habitable zone (darker green shade is the conservative habitable zone and the lighter green shade is the optimistic habitable zone). Only those planets less than 10 Earth masses or 2.5 Earth radii are labeled. Some are still unconfirmed (* = unconfirmed). The different limits of the habitable zone are described in Kopparapu et al. (2014). Size of the circles corresponds to the radius of the planets (estimated from a mass-radius relationship when not available). Larger version here. Credit: PHL @ UPR Arecibo